The invention relates to a process for extruding a billet to a hollow section, in particular a light metal billet which is situated in a container and is extruded through the shape-giving opening or orifice of a die which accommodates a mandrel determining the internal contour of the hollow section. Also within the scope of the invention is a device for extruding with an extrusion stem.
A device of this kind and a corresponding process are described in the U.S. Pat. No. 3,240,047, and namely employing a weld-chamber type die which supports a plurality of fixed mandrels on a bridging part of the die, the shaft of which is surrounded at a distance therefrom by a die ring.
This die is intended for the production of tubes which feature so-called extrusion welds running in the direction of extrusion and therefore exhibit a non-uniform structure when viewed in cross-section.
Applications exist for tubes or the like hollow sections which must exhibit not only a seamless wall body, but should also feature a flange at the end of the tube--and this with as little change in structure as possible. Such an application exists for example in the form of containers for uranium separation plants; these containers comprise a tube body with flange at one end. The latter part is usually welded-on and subsequently machined etc.
In view of the above, the object of the present invention is to produce, in one piece and as economically as possible, a hollow section with integral flange at the end.